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TPS659XX prevent power up on VBAT

Cliff Brake
Intellectual 420 points

Hello, 

I am interested if there is any way to prevent a TPS659XX system from powering up until the power button is pressed?  We have a situation where a charger wants to trickle charge a dead battery and if we try to power up during this state, the charger things the battery cells are shorted.  It seems the STARTON_VBAT bit would help us there, but it defaults to high, and must be programmed by software.  However, in a dead system, we can't run software.  I tried holding PWRON and RESPWRON low, and in this case the system draws up to 140mA, and then settles at 37mA, so this won't work either.  We are trying to avoid having to manage the entire power path, but its looking like we might have to.

Thanks,

Cliff

 

  • 0
    TI__Genius 15100 points

    Hi Cliff,

    I dont understand your system situation. What is the relation between trying to power ON and trickle charging phase. The device will not power ON till the battery reaches 3.2V.

    If you are looking at first power up then there is no way to avoid the default power up. In case this is after the first power up then it is possible if you have a back up battery. STARTON_VBAT is part of the backup domain and will retain the new value as long as backup battery is present.

    Hope this helps.